Vehicle capable of low noise runs

ABSTRACT

A vehicle comprises electric motor, generator of simulated engine sounds, decider of whether or not to generate simulated engine sounds and controller of the level of simulated engine sounds. The controller smoothly increases level of simulated engine sounds upon decision of sound generation on detection of pedestrian, crosswalk, narrow road, or road with no sidewalk. The decider is responsive to vehicle navigation system, or ETC, or camera of EDR. EDR records the decision as circumstantial evidence. The decision may be optionally possible, but is forcibly made upon necessity. Simulated engine sounds can be greater than, or equal to, or less than real engine sounds. The controller makes a soft peak of simulated engine sound upon brake or accelerator operated. Balance of simulated engine sounds among front, rear, right and left of vehicle is changeable in response to shift lever or blinker lever operation. The decision is visually indicated inside vehicle.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation Application of U.S. application Ser.No. 12/901,537 filed Oct. 10, 2010 herein incorporated by reference inits entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a vehicle capable of low noise runs

2. Description of the Related Art

In this field of the art, various attempts have been done with respectto a vehicle capable of low noise runs. Examples of vehicles capable oflow noise runs include hybrid vehicles and electric vehicles which arefavorable to quiet environment. On the other hand, the almost silent runof a hybrid or electric vehicle at lower speed means a problem forvisually impaired pedestrians who rely more on audio inputs to know whatis going around them have a problem. To solve the problem, it isproposed to mount speakers externally with a controller tied to theaccelerator pedal. The system generates simulated engine sounds thatwill allow people in the vicinity hear the car approach.

On the other hand, Japanese Publication No. 2005-289175 proposes a fuelcell car capable of generates simulated engine sounds that will allowpeople in the vicinity hear the car approaching at lower speed.According to the proposal, simulated engine sounds are generated by anelectronically controlled unit on the basis of a sensor for detectingrevolution speed of a driving motor. The level of simulated engine soundis determined in accordance with revolution speed of air compressor lessthan a threshold when the speed of vehicle sensed by speedometer sloweddown less than a threshold. The simulated engine sounds thus determinedare emitted to the outside form a speaker to inform pedestrians of thecar approach. Further, it is proposed to additionally prepare anenvironment signal generating means for the purpose of determining thelevel of simulated engine sounds in accordance with the speedometer orthe environment signal generating means. The environment means thepresence or absence of pedestrian, or daytime or evening or night time,area where vehicle runs, or the level of noise outside the vehicle.

However, there still exist in this field of art many demands forimprovements of a vehicle capable of low noise runs vehicle system.

SUMMARY OF THE INVENTION

Preferred embodiments of this invention provide a vehicle capable of lownoise runs in which warm and safe coexistence of both vehicles andpedestrians is possible.

Preferred embodiments of this invention provide a vehicle capable of lownoise runs in which the original advantage of low noise runs isharmonized with the safety of pedestrians.

Preferred embodiments of this invention provide a vehicle capable of lownoise runs with a possible misunderstanding between the driver insideand pedestrian outside of the vehicle avoided.

In a detailed design according to the above preferred embodiment, avehicle capable of low noise runs is proposed, the vehicle comprising anelectric motor for driving the vehicle, a sound generator arranged togenerate simulated engine sounds outside the vehicle for pedestrians tohear the vehicle, a decider arranged to decide whether or not to havethe sound generator generate the simulated engine sounds, and acontroller arranged to change the level of the simulated engine soundsin accordance with a predetermined manner.

The decider above is advantageous to limit the generation of thesimulated engine sounds to a case of necessity for a pedestrian and tokeep the low noise runs in the other case. The controller above isadvantageous in view of warm and safe coexistence of both vehicles andpedestrians.

In more detail, the controller is arranged to smoothly increase thelevel of the simulated engine sounds when the decider decides to havethe sound generator start generating the simulated engine sounds. Thus,the controller is functioning not to astonish people in the vicinity ofvehicle with sudden and artificial emergence of the simulated enginesounds in response to the decider.

According to further detailed design, the decider is arranged to havethe sound generator generate the simulated engine sounds in response toa detection of a pedestrian in the vicinity of the vehicle, or inresponse to a detection that the vehicle is close to a crosswalk, or inresponse to detection that the vehicle is on narrow road, or in responseto a detection that the vehicle is on a road with no sidewalk. Thesesituations are considered to be a case of necessity for a pedestrian tobe informed of the vehicle to approach or to start moving in thevicinity.

According to another detailed design, the vehicle further comprises avehicle navigation system unit, wherein the decider is arranged to makethe decision in response to the vehicle navigation system unit. Thevehicle navigation system unit is possibly an advantageous source ofinformation relating to crosswalk, narrow road, or a road with nosidewalk.

According to still another detailed design, the vehicle furthercomprises an electronic toll system unit, wherein the decider isarranged to make the decision in response to the electronic toll systemunit. The electronic toll system unit is possibly an advantageous sourceof information for the decision by the decider since there is lesspossibility of pedestrian walking on the toll road and the meaninglessand rather harmful generation of the simulated engine sounds upontraffic jam in toll way should be inhibited.

According to another detailed design, the vehicle further comprises acamera unit, wherein the decider is arranged to make the decision inresponse to the camera unit. The camera unit, which may be installed inthe vehicle to capture outside image for an event data recorder forexample, is possibly an advantageous source of information of pedestrianin the vicinity of the vehicle. In more detail, the captured image maygive information of a pedestrian putting up an umbrella who may needshigher volume of the simulated engine sounds under high noise caused byrain drops on his or her umbrella.

According to still another detailed design, the vehicle furthercomprises an event data recorder unit arranged to record the decision bythe decider. The record of the fact whether or not the simulated enginesounds was generated upon an accident or the like may constitute acircumstantial evidence. According to more detailed design, the vehiclefurther comprises manually setting unit, wherein the decider is arrangedto make the decision in response to the manually setting unit. In thiscase, the feature of recording the decision into event data recorderunit may have a driver who sets the non-generation of the simulatedengine sounds on his or her responsibility become more careful indriving the vehicle under such setting.

According to another detailed design, the vehicle further comprises amanually setting unit, wherein the decider is arranged to normally makethe decision in response to the manually setting unit and to have thesound generator generate the simulated engine sounds under apredetermined condition regardless of the manually setting unit. In thisdetailed design, a driver can manually set the non-generation of thesimulated engine sounds on his own decision to normally prefer silenttravel while the simulated engine sounds can be automatically andforcibly generated upon necessity such as on an occasion of appearanceof a pedestrian.

According to still another detailed design, the controller is arrangedto make a peak of the level of the simulated engine sounds by softlyincreasing and then decreasing the simulated engine sounds. In thismanner of control, pedestrians may naturally and more clearly notice thesimulated engine sounds. In more detailed design, the vehicle furthercomprises an operating portion for operation of one of a brake and anaccelerator, wherein the controller in arranged to make the peak inresponse to the operation at the operating portion. This detailed designis advantages for a driver to naturally and courteously notice thepedestrians of the existence of vehicle with the simulated engine soundsat a crawl in a narrow road filled by pedestrians.

According to another detailed design, the vehicle further comprises agasoline engine for driving the vehicle, wherein the controller isarranged to set the level of the simulated engine sounds to one of alevel greater than the real gasoline engine sounds, a levelsubstantially equal to the real gasoline engine sounds and a level lessthan the real gasoline engine sounds. According to the design that thelevel of the simulated engine sounds is greater than the real gasolineengine sounds, pedestrians under foul weather or the like where highenvironmental noise is assumed can more easily hear the approach of thevehicle than in the case the real engine sounds generation. On the otherhand, according to the design that the level of the simulated enginesounds is substantially equal to the real gasoline engine sounds, aseamless transition between the real engine sounds and the simulatedengine sounds is possible. In this instance, a simulated engine soundpreparation by means of sampling and recording the real engine sounds ofown vehicle is advantageous. Further, according to the design that thelevel of the simulated engine sounds is less than the real gasolineengine sounds, a suitable simulated engine sounds generation is possibleunder such an environment that the real engine sounds are too much, butmere tire noise may be drowned out by the environmental noise.

In another detailed design according to the above preferred embodiment,a vehicle capable of low noise runs is proposed, the vehicle comprisingan electric motor for driving the vehicle, a sound generator arranged togenerate simulated engine sounds outside the vehicle for pedestrians tohear the vehicle including a plurality of generating portions, anoperating portion for operation of the vehicle, and a controllerarranged to change the balance among the levels of the simulated enginesounds from the plurality of generating portions in response to theoperation at the operating portion. According to this feature,pedestrians especially involved in the in movement of the vehicleeffectively hear the approach or presence of the vehicle. In moredetail, the controller is arranged to change one of the balances of thesimulated engine sounds between the front and the rear of the vehicleand between the right and the left of the vehicle. In the case ofcontrolling balance of simulated engine sound level between the frontand the rear of the vehicle, the front side level is increased uponforward travel of the vehicle while the rear side level is increasedupon reverse travel, the control being in response to the operation ofselect lever, for example. On the other hand, in the case of controllingbalance of simulated engine sound level between the right and the leftof the vehicle, the right side level is increased upon right turn of thevehicle while the left side level is increased upon left turn, thecontrol being in response to the operation of blinker lever, forexample.

In another detailed design according to the above preferred embodiment,a vehicle capable of low noise runs is proposed, the vehicle comprisingan electric motor for driving the vehicle, a sound generator arranged togenerate simulated engine sounds outside the vehicle for pedestrians tohear the vehicle, a decider arranged to decide whether or not to havethe sound generator generate the simulated engine sounds, and a visualindicator arranged to inform the driver inside the vehicle of thedecision by the decider. The indication of the decision inside thevehicle where quietness is kept against outside noise is an effectivehelp for the driver to become aware of the simulated engine soundsgeneration for avoiding such an inconsistency that the driver gets afalse idea of no generation of the simulated engine sounds though thepedestrian actually hears the simulated engine sounds, or vice versa.

Other features, elements, arrangements, steps, characteristics andadvantages according to this invention will be readily understood fromthe detailed description of the preferred embodiments in conjunctionwith the accompanying drawings.

The above description should not be deemed to limit the scope of thisinvention, which should be properly determined on the basis of theattached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a vehicle with a simulated enginesound generator according to an embodiment of this invention.

FIG. 2 is a flowchart showing the function carried out by vehiclecontroller of the embodiment in FIG. 1.

FIG. 3 is a flowchart showing the detailed function of the engine soundsgeneration process during run in step S22 in FIG. 2.

FIG. 4 is a flowchart showing the detailed function of the motor runprocess in step S36 in FIG. 2.

FIG. 5 is a flowchart showing the detailed function of the simulatedengine sounds generation process in steps S18 and S22 in FIG. 2, stepS62 and step S104 in FIG. 4.

FIG. 6 is a flowchart showing the detailed function of the volumemodification process in steps S138 in FIG. 5.

FIG. 7 is a flowchart showing the detailed function of the simulatedengine sounds indication process in steps S16 in FIG. 2, S60 in FIGS. 3and S102 in FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a block diagram showing a vehicle with a simulated enginesound generator according to an embodiment of this invention. Vehicle 2is shown as a so-called hybrid car powered by both a gasoline engine andelectric motor. Vehicle 2 includes vehicle controller 4 having computerfor controlling vehicle function unit 8 in response to operating portion6 including brake 1, accelerator 3, steering wheel 5, select lever 7 forthe automatic transmission, which are to be operated by a driver. Thefunctions of vehicle controller 4 are carried out in accordance withsoftware stored in memory 10. Memory 10 further stores various temporarydata necessary for controlling entire vehicle 2 as well as variousinformation gotten inside or outside vehicle 2. Operating portion 6further includes various supplementary members for operating additionalfunctions, such as blinker lever 9 for operating blinkers.

Vehicle controller 4 further controls display 12 for graphic useinterface (GUI) in cooperation with setting unit 14 and for indicationof the result of control or calculation. Setting unit 14 includes aswitch for selecting between the standard hybrid running mode and aforcible electric running mode. The forcible electric running mode isfor solely using electric motor regardless of the running condition asin an electric car, in constant to the standard hybrid running mode inwhich the gasoline engine and electric motor are automaticallyinterchanged depending on the running condition. Such the forcibleelectric running mode is advantageously set for realizing a silentrunning without fail in a late-night residential area. As will bementioned later in detail, vehicle 2 is designed to generate simulatedengine sound with vehicle driven by the electric motor in the standardhybrid running mode. According to a feature of this invention, thesimulated engine sound is automatically inhibited with vehicle 2 setinto the forcible electric running mode at bottom. In this regard,however, the inhibited simulated engine sound is forcibly restored evenin the forcible electric running mode if vehicle 2 detects a person at ashort distance or vehicle 2 approaches a crossing or the like where aperson may exist in a relatively high provability.

Vehicle controller 4 includes clock 16, the clock time of which isutilized in various functions. For example, according to a feature ofthis invention, the volume of the simulated engine sounds isautomatically increased in daytime so that pedestrians may easily hearthe approach of vehicle 2 under presumed high environmental noise. Onthe other hand, the volume of the simulated engine sounds isautomatically decreased in late-night time to a level less than that ofa real engine noise so as to avoid unnecessary sound generation whichmay otherwise harm the presumed silent environment. The clock time ofclock 16 utilize in the above sound volume control or the like is oftenand automatically set right by means of ratio wave time informationoutside.

Global positioning system (GPS) unit 18 receives the absolute positioninformation of vehicle 2 including latitude, longitude and altitude fromthe satellite and the nearest broadcast station according to GPS, whichinformation being sent to vehicle controller 4. Vehicle navigationsystem unit 20 processes the absolute position information coming fromGPS unit 18 by way of vehicle controller 4 to indicate the position ofvehicle 2 on map 22 in display 12. The information from vehiclenavigation system 20 is utilized to automatically control the generationof the simulated engine sounds in such a manner that the simulatedengine sounds are automatically generated in a residential roads area orthe like where pedestrians may exist in a high probability, while thesimulated engine sounds are automatically muted on highway or the likewhere pedestrians may not exist in a high probability. Especially, on aroad without sidewalk or a narrow road without center divider, thesimulated engine sounds are automatically generated in the highestpriority. The types of areas with or without the simulated engine soundsgeneration are distinguishable from each other by different colors inmap 22, which informs the driver of whether vehicle 2 is currentlyrunning with or without the simulated engine sounds generated.

Vehicle 2 is also provided with short-range wireless communicator 24capable of communicating with wireless communications installed invarious equipment or machine on a road, such as traffic light or a signfor crosswalk, located at places where pedestrians may cross the road.Thus, vehicle 2 can automatically begin generating the simulated enginesounds when wireless communicator 24 comes to receive signal form one ofthe traffic lights or signs by means of approaching it, and alsoautomatically stop generating the unnecessary simulated engine soundswhen wireless communicator 24 can no more receive signal form thetraffic light or the sign by means of leaving it. In place of or inaddition to short-range wireless communicator 24, the information fromvehicle navigation system 20 is further utilizable to automaticallycontrol the above mentioned generation of the simulated engine sounds atplaces where pedestrians may cross the road since the information fromvehicle navigation system 20 includes the locations of the trafficlights or crosswalks.

Electronic toll system (ETC) unit 26 receives at toll gate or the likethe information of the motorway toll for storage in memory 10 by way ofvehicle controller 4. The location information from vehicle navigationsystem unit 20, or the information of possible existence of pedestriansfrom short-range wireless communicator 24, or the information of goinginto or out of a toll highway form ETC unit 26, or one of variouscombinations thereof is utilizable to automatically control thegeneration of the simulated engine sounds in accordance with the area inwhich vehicle 2 is running. For example, the simulated engine sounds areautomatically generated on a residential road or local road outside atoll highway where pedestrians may exist in a high probability, whilethe simulated engine sounds are automatically muted in an area wherepedestrians may not exist in a high probability.

Vehicle function unit 8 includes gasoline engine 30 and electric motor32 for generating power to be transmitted to drive mechanism 28 havingtransmission and wheels. Fuel flow meter 34 measures fuel flow injectedinto gasoline engine 30 through injection valve to inform vehiclecontroller 4 of the measured fuel flow. Odometer 36 calculates the runof vehicle 2 by multiplying the known diameter of the wheel in drivemechanism 28 by the number of rotations thereof to inform vehiclecontroller 4 of the calculated run. Thus, vehicle controller 4calculates the flash fuel cost on the basis of the fuel flow and the runto indicate it at flash fuel cost area 38 in display 12. Vehiclecontroller 4 further calculate average fuel cost on the basis of theflash fuel cost to indicate the results in display 12 at fuel cost area38.

Display 12 further includes speedometer area 42 for indicating the speedof vehicle 2 in accordance with the information from drive mechanism 28by way of vehicle controller 4. The color for indicating the speed inspeedometer area 42 is designed to differ between conditions with andwithout generation of the simulated engine sounds to inform the driverof whether or not the simulated engine sounds are actually generated.Thus, the driver is capable of sharing the fact of the simulated enginesounds generation with the pedestrians outside since the simulatedengine sounds is hardly audible within vehicle 2. Display 12 alsoincludes select lever indicator are 40 for indicating one of selectlever positions, “P”, “R”, “N”, “D”, and “L”.

The followings are explanation for the details of how to generate thesimulated engine sounds. Outside microphone 44 is to pick up soundsoutside vehicle 2 for dual purposes. The first purpose or function ofoutside microphone 44 is to sample own engine sounds of vehicle 2 bymean of practicing dummy runs with gasoline engine 30 under variousrunning conditions prior to the shipping, the sampled engine soundsbeing transmitted to vehicle controller 4 for recordation. Thus, thesimulated engine sounds in this case are created based on own realengine of vehicle 2. This realizes a seamless transition between thereal engine sounds and the simulated engine sounds since the origin ofsounds are both the same. In taking the simulated engine sounds, thestarting-up and low speed running in the dummy runs are forcibly carriedout by gasoline engine 30 even in the standard hybrid running modesetting in which the starting-up and low speed running are normallycarried out by electric motor 32.

Vehicle controller 4 controls sound memory 46 to record the enginesounds picked up by outside microphone 24 in relationship to theinformation of operating condition of accelerator 3 and the fuel flowdetected by fuel flow meter 34 at the time of sampling the enginesounds. Accordingly, sound memory 46 records a correlation table ofengine sound data 48 and its volume changing pattern data 50 in relationto the information of operating condition of accelerator 3 and the fuelflow detected by fuel flow meter 34 for various running conditions.Sound memory 46 further stores ultrasonic sound data 52 for guide dog.The ultra sonic sound is to be generated in the motor running conditionin place of the simulated engine sounds to inform a guide dog of theapproach of vehicle 2 in the late-night residential area, where enginenoise is harmful.

The second purpose or function of outside microphone 44 is to pick upenvironmental noise during actual run by electric motor 32 toautomatically control the volume of the simulated engine sounds inaccordance with the environmental noise. The automatic control of thevolume is carried out in such a manner that the volume of the simulatedengine sounds is increased to a level greater that that of real enginesounds in the case of environmental noise over a first limit so thatpedestrians may easily hear the approach of vehicle 2. On the otherhand, the volume of the simulated engine sounds is decreased to a levelless that that of real engine sound in the case of environmental noiseless than a second limit so as to avoid unnecessary sound generationwhich may otherwise harm the silent environment.

Outside speaker 54 includes front speaker unit 56 for forward travel andrear speaker unit 58 for reverse travel, the volume balance of simulatedengine sounds being so controlled that the volume of one of frontspeaker unit 56 and rear speaker unit 58 is greater than that of theother in accordance with the traveling direction of vehicle 2 controlledby the operation of select lever 7. Outside speaker 54 further includesright speaker unit 60 and left speaker unit 62, the volume balance ofsimulated engine sounds being so controlled that the volume of one ofright speaker unit 60 and left speaker unit 62 is greater than that ofthe other in response to the operation of blinker lever 9 indicating theturning direction of vehicle 2. Thus, pedestrians to be approached byvehicle 2 may easily hear the simulated engine sounds, while pedestriansto be left by vehicle 2 may not be suffered from unnecessary simulatedengine sounds.

Motion sensor 64 is for detecting the existence of pedestrians by theirmotions to automatically generate the simulated engine sounds so thatthe pedestrians may notice the approach of vehicle 2. On the other hand,unnecessary simulated engine sounds are not generated if motion sensor64 does not detect any pedestrian around vehicle 2. Upon generation ofthe simulated engine sounds in response to motion sensor 64, the volumeof the simulated engine sounds is softly increased from zero level notto astonish the pedestrians with simulated engine sounds otherwisegenerated suddenly in the vicinity. Weather sensor 66 is for detectingrain drops on vehicle 2 or low barometric pressure to automaticallyincrease the volume of the simulated engine sounds to a level greaterthan that of the real engine sounds under foul weather so thatpedestrians possibly putting up their umbrellas may easily hear theapproach of vehicle 2 under presumed high environmental noise caused byrain or wind. On the other hand, the volume of the simulated enginesounds is automatically decreased in fine weather so as to avoidunnecessary loud simulated engine sounds generated.

Event data recorder unit (EDR) 68 is for recording various eventsrelating to the travel of vehicle 2 including front and rear road imagescaptured by camera unit 70. EDR unit 68 is arranged to further recordthe operations at operating portion 6 and the settings at setting unit14 by the driver on its responsibility. Accordingly, such a condition isto be recorded on EDR 68 that vehicle 2 is running in the forcibleelectric running mode in which the simulated engine sound isautomatically inhibited. Such a record may constitute a circumstantialevidence if an accident will unfortunately occur due to an injuredperson unable to notice a silent approach of vehicle 2. Thus, a driverwho sets the forcible electric running mode becomes more careful indriving under such setting.

The image captured by camera unit 70 is processed to detect an existenceof a pedestrian putting up umbrella to automatically increase the volumeof the simulated engine sounds to a relatively high level so that thepedestrian may easily hear the approach of vehicle 2 under high noisecaused by rain drops on his or her umbrella. On the other hand, thevolume of the simulated engine sounds is not so increased if nopedestrian putting up umbrella is detected through processing the imagefrom camera unit 70. This automatic volume control in response to thedetection of a pedestrian actually putting up umbrella can be combinedwith the automatic volume control in response to weather sensor 66explained above.

For the purpose of polite notice in shopping area or the like in whichnarrow roads are crowded with pedestrians, vehicle 2 is arranged togenerate the simulated engine sounds with its volume changed inaccordance with natural and soft wave pattern in response to frequentrepetitions between operations of brake 1 and accelerator 3, which areordinarily and naturally experienced when going at a crawl. The abovewaveform pattern of changing the volume of the simulated engine soundsis a copy of the change in volume of real engine sounds upon crawl whichare the natural result of the above mentioned frequent repetitionsbetween brake and accelerator operations. Thus, warm coexistence of bothvehicles and pedestrians in shopping area or the like is realized withunpleasant horn or factitious electric melody notice avoided.

FIG. 2 is a flowchart showing the function carried out by vehiclecontroller 4 of the embodiment in FIG. 1. Vehicle controller 4 isbasically a computer, the flowchart in FIG. 2 showing the function ofthe computer. The flowchart starts when vehicle 2 becomes into acondition for ready to run. The condition for ready to run includes theactually running condition. In detail, the flow starts with the electricswitch for ready to run turned from the off position to the on position.If the flow starts, a process for initial check of vehicle function unit8 is carried out. The initial check process in step S2 includes a visualindication and audio announce of the result of the check.

Next in step S4, it is checked whether or not the sampling of realengine sounds are completed to get the simulated engine sounds. If not,the flow goes to step S6 to automatically set vehicle 2 into theforcible engine running mode for dummy runs, in which sole gasolineengine 30 is made active with electric motor not used during idling aswell as all running condition including low speed running. Thus, realengine sounds are to be generated in dummy runs for sampling. Then, theflow advances to engine sounds sampling process in step S8, in whichvarious running conditions beginning with the starting of the gasolineengine 30 are directed in accordance with a predetermined program storedin memory 10 to successively cause various engine sounds correspondingto each running condition and transitions between the runningconditions. The engine sounds thus generated are successively sampledand stored in sound memory 46 as engine sound data 48 for variousrunning conditions and volume changing pattern data 50 into acorrelation table in relation with the information of operatingcondition of accelerator 3 and the fuel flow detected by fuel flow meter34. Upon completion of step S8, the flow goes back to step S4 to checkagain whether or not the sampling of real engine sounds are completed.The loop of steps S2 to S8 is repeated as long as engine sounds samplingis incomplete, during which the standard hybrid running is inhibited.

On the other hand, if it is determined in step S4 that the sampling ofreal engine sounds had just been completed or vehicle 2 is in thestandard hybrid running mode with the sampling of real engine soundscompleted, the flow advances to step S10. Since the engine soundssampling process in step S8 has normally been completed prior to theshipping, the flow in FIG. 2 goes form step S4 directly to step S10 ifthe flow is stated by an ordinary owner of vehicle 2 with the electricswitch for ready to run turned from the off position to the on position.

In step S10 it is checked whether or not the forcible motor running modeis set. If not, the flow goes to step S12 to automatically set thestandard hybrid running mode. The flow then goes to step S14 to checkwhether or not motion sensor 64 detects any pedestrian exists in thevicinity of vehicle 2. If any, the flow advances to step S16 to carryout engine sounds indication process, in which the fact of generatingthe simulated engine sounds is indicated within vehicle 2 so that thedriver inside vehicle 2 may know the generation of the simulated enginesounds outside, the details of the engine sound indication process beingexplained later. Next in step S18, engine sounds generation process iscarried out to go to step S20, the details of the engine soundindication process in step S18 being also explained later. Thus, even ina condition that vehicle 2 is stopped, the simulated engine sounds ofstarting up or idling are generated as in the case of gasoline enginevehicle if motion sensor 64 detects a pedestrian in the vicinity ofvehicle 2.

In step S20, it is checked whether or not a start operation to run. Ifthe start operation is detected in step S20, the flow going to theengine sounds generation process during run in step S22, the details ofthe engine sound indication process being explained later. If the enginesounds generation process during run in step S22 has been completed, theflow goes to step S24 to check whether or not vehicle 2 stops inresponse to the operation by brake 1. If not, the flow goes back to stepS22 to repeat steps S22 and S24 unless vehicle 2 stops, the simulatedengine sounds generation continuing during the repetition.

On the other hand, if it is detected in step S24 that vehicle 2 stops inresponse to the operation by brake 1, the flow goes to step S26 to checkwhether or not the electric switch for ready to run is turned from theon position to the off position. If the switch off is detected in stepS26, the flow goes to the end. By the way, if it is determined in stepS14 that motion sensor 64 detects no pedestrian exists in the vicinityof vehicle 2, the flow goes to step S28 to inhibit generation of thesimulated engine sounds. Further in step S30, the driver is informed byan indication within vehicle 2 of the fact hat no simulated engine soundis generated outside vehicle 2, the flow then going to step S20. Thus,the simulated engine sounds are not generated with no pedestrianexisting in the vicinity of vehicle 2 even when the electric switch forready to run is turned from the off position to the on position, whichtakes over such an advantage of conventional hybrid vehicles that noengine sound arises during idling or low speed running to keepenvironmental silence.

If it is detected in step S10 that the forcible motor running mode isset, the flow goes step S32 to inhibit generation of the simulatedengine sounds. Further in step S34, the driver is informed by anindication within vehicle 2 of the fact that no simulated engine soundis generated outside vehicle 2, the flow then going to step S36. In stepS36, motor run process is forcibly carried out to realize motor run fromstart up till stopping of vehicle 2, the details of which will beexplained later. If the motor run process in step S36 has beencompleted, the flow goes to step S26. Thus, the simulated engine soundsare not generated in principle with the forcible motor running mode setexcept for a case of necessity for keeping safety.

If no start operation is detected in step S20, the flow goes back tostep S10 to deal with a possible change in operation to set the forciblemotor running mode in idling state. The loop of steps S10 to S20 andsteps S28 and S30 is repeated as long as the forcible motor running modeis not set. Thus, it is automatically decided to or not to generate thesimulated engine sounds in response to the change in detection ofpedestrians by motion sensor 64 in step S14 during the repetition of theloop. In other words, if the sensed pedestrian comes off vehicle 2 withthe simulated engine sounds generated, the generation is automaticallystopped to get back to silence. On the other hand, if a pedestrianapproaches vehicle 2 with no simulated engine sound generated, thesimulated engine sounds are automatically start to be generated. In thiscase, the volume of the simulated engine sounds is softly and naturallyincreased from zero level not to astonish the sensed pedestrian, thevolume control in this manner being explained later in more detail. Bythe way, if it is not detected in step S26 that the electric switch forready to run is turned from the on position to the off position, theflow returns to step S10 to repeat the loop of steps S10 to S36 fordealing with various changes in situation or setting.

FIG. 3 is a flowchart showing the detailed function of the engine soundsgeneration process during run in step S22 in FIG. 2. If the flowchartstarts, it is checked in step S42 whether or not the forcible motorrunning mode is set. If the forcible motor running mode setting isdetected in step S42, the flow goes to step S32 in FIG. 2. Thus, thechange in setting to the forcible motor running mode is possible duringrun. On the other hand, if it is not detected in step S42 that theforcible motor running mode is set, the flow goes to step S44 to checkwhether or not vehicle 2 is running by gasoline engine. If not, the flowgoes to step S46 to check whether or not vehicle 2 is running on tollhighway. If not, the flow further goes to step S48 to check whether ornot motion sensor 64 detects any pedestrian. If not, the flow furthergoes to step S50 to check on clock 16 whether or not it is in late-nighttime zone in which silence is required, e.g., 22:00 to 5:00. If inlate-night time zone, the flow goes from step S50 to S52 to check onoutside microphone 44 whether or not environmental noise is less than alimit considered to be silence.

If it is determined in step S50 that it is not in late-night time zone,the flow advances to step S54. Further, if it is determined in step S52that environmental noise is greater than the limit, the flow advances tostep S54. The steps led by step S54 are for deciding whether or not togenerate the simulated engine sounds on a probability of existence ofpedestrians. Initially in step S54, it is checked whether or not vehicle2 is on a narrow road without center divider for example in accordancewith the information form vehicle navigation system unit 20. If not, theflow goes to step S56 to check whether or not vehicle 2 is running on aroad without sidewalk also in accordance with the information formvehicle navigation system unit 20. If not, the flow further goes to stepS58 to check whether or not vehicle 2 is approaching a crosswalk inaccordance with information from vehicle navigation system unit 20 orshort-range wireless communicator 24, or combination of thoseinformation. If it is determined in step S58 that vehicle 2 isapproaching a crosswalk, the flow goes to step S60 to carry out enginesounds indication process, which is similar to the process in step S16in FIG. 2.

On the other hand, if it is determined in step S48 that motion sensor 64detects any pedestrian, the flow directly goes to step S60. Further, ifit is determined in step S54 that vehicle 2 is on a narrow road, theflow directly goes to step S60. Still further, if it is determined instep S56 that vehicle 2 is running on a road without sidewalk, the flowdirectly goes to step S60. Following step S60, engine sound generationprocess is carried out in step S62, which is similar to the process instep S18 in FIG. 2, the flow then going to step S64.

If it is determined in step S44 that vehicle 2 is running by gasolineengine, the flow goes to step 66 to inhibit the ultrasonic sound forinforming guide dog of the approach of vehicle 2. The flow further goesto step 68 to inhibit the simulated engine sounds. Further in step S70,the driver is informed by an indication within vehicle 2 of the fact hatno simulated engine sound is generated outside vehicle 2, the flow thengoing to step S64. Thus, the ultrasonic sound and the simulated enginesounds are inhibited when vehicle 2 is running by real gasoline engine30 since they are redundant in the condition that real engine sounds aregenerated. However, such a modification is possible that the ultrasonicsound and the simulated engine sounds are not inhibited but are added toreal engine sounds with volume higher that that of the real engine soundin the condition that the environmental noise is greater than a limit,or weather is foul, or a pedestrian puts up an umbrella, or the likewhere high noise possibly drowning out the real engine sounds areexpected. The generation of the ultrasonic sound and the simulatedengine sounds with high volume in the above conditions can be possiblein the similar manner in the flow in FIG. 5 explained later.

Similarly, if it is determined in step S46 that vehicle 2 is running ontoll highway, the flow goes to the steps led by step 66 to inhibit theultrasonic sound and the simulated engine sounds with the driver withinvehicle 2 informed of the inhibition, the flow then going to step S64.Thus, the ultrasonic sound and the simulated engine sounds are inhibitedwhen vehicle 2 is running on toll highway where no pedestrian isexpected. The inhibition is reasonable in toll highway in that thesimulated engine sounds may otherwise be meaninglessly and ratherharmfully generated upon traffic jam in toll high way since gasolineengine 30 will be automatically switched into the silent electric motor32 when the speed of vehicle 2 is lowered due to the traffic jam.

If the late-night is determined in step S50 and the low environmentalnoise is successively determined in step S52, The flow goes to step S72to determine whether or not vehicle 2 is in the residential are inresponse to the information form vehicle navigation system unit 20. Ifit is determined in step S72 that vehicle 2 is running in residentialarea, the flow goes to step 66 to inhibit generation of ultrasonic soundprior to going to step S68. This is because that many pet dogs areexpected to belong to residential area homes whereas it may be very rarethat a pedestrian with a guide dog is in the street at late-night. So,it is reasonable to inhibit the ultrasonic sound in residential area atlate-night not to irritate the pet dogs to tongue with meaninglessultrasonic sound. Next in step S68, the generation of simulated enginesounds is inhibited with the driver within vehicle 2 informed of theinhibition in step S70, the flow then going to step S64. This is becausethat the simulated engine sounds may merely destroy the advantage ofhybrid vehicle 2 capable of silent run with electric motor 32 in spiteof the low possibility of pedestrian in the late-night residential areastreet. Even if any pedestrian in the street, he or she is expected tonotice the approach of vehicle 2 with its tire noise or the like in thesilence of residential area at late-night.

On the other hand, if residential is not determined in step S72, theflow goes to step S74 to generate the ultrasonic sound prior to going tostep S68 since it is less probable that a pet dog belongs to anon-residential area than that a pedestrian with a guide dog is in thestreet. Thus, even in such a case that the simulated engine sounds areinhibited with silent late-night environment taken into consideration,the generation under permissible condition of ultrasonic sound audiblefor dogs and harmless to human ears is advantageous to avoid an accidentat crosswalk between a motor running silent vehicle and a pedestrianwith a guide dog.

In step S64, it is checked whether or not an operation to stop vehicle 2is made by brake 1. If such an operation is detected in step S64, theflow goes to the end to advance to step S24 in FIG. 2. On the otherhand, if such an operation is not detected in step S64, the flow goesback to step S42 to repeat steps S42 to S74 unless the stop operation isdetected in step S64.

FIG. 4 is a flowchart showing the detailed function of the motor runprocess in step S36 in FIG. 2, in which motor run is forcibly carriedout from start up till stopping of vehicle 2. If the flowchart starts,it is checked in step S82 whether or not vehicle 2 is in one of therunning condition or a condition with the operation to run having beendone. If vehicle 2 is not in any of these conditions, the flow instantlygoes to the send to advance to step S26 in FIG. 2.

On the other hand, if it is determined in step S82 that vehicle 2 is inone of the running condition or a condition with the operation to runhaving been done, the flow goes to step S84 to check whether or notmotion sensor 64 detects any pedestrian exists in the vicinity ofvehicle 2. If not, the flow goes to step S86 to check whether or notvehicle 2 is approaching a crosswalk in accordance with information fromvehicle navigation system unit 20 or short-range wireless communicator24, or combination of those information. If not, the flow goes to stepS88 to check whether or not frequent repetitions of alternatingoperations of brake 1 and accelerator 3 are made. Such alternatingoperations are typically experienced at a crawl in a narrow road filledby pedestrians. If not, the flow goes to step S90.

The above steps S84 to S88 are for determining whether or not vehicle 2is in one of the conditions to exceptionally generate the simulatedengine sounds in spite of the forcible motor running mode set with anintention to achieve a silent run. If vehicle 2 is not any of suchconditions, the flow goes to step S90 to inhibit the simulated enginesounds generation. Further, in step S92, the driver is informed by anindication within vehicle 2 of the fact that no simulated engine soundis generated outside vehicle 2, the flow then going to step S94.

In step S94, it is checked, whether or not vehicle 2 is in theresidential are in response to the information form vehicle navigationsystem unit 20. If not, the flow goes to step S94 to generate ultrasonicsound prior to going to step S98. On the other hand, if the residentialarea is determined in step S94, the flow goes to step S100 to inhibitgeneration of ultrasonic sound prior to going to step S98. The meaningof the above steps S94, S96 and S100 is similar to that of steps S72,S74 and S66. In other words, even in such a case that the simulatedengine sounds are inhibited in accordance with the forcible motorrunning mode setting, the generation under permissible condition ofultrasonic sound is advantageous to avoid an accident at crosswalkbetween a motor running vehicle and a pedestrian with a guide dog.

In step S98, it is directed to record on EDR unit 68 the fact whether ornot the simulated engine sounds and ultrasonic sound are generated aswell as various events which have occurred during the run of vehicle 2.Accordingly, such a condition is to be recorded on EDR 68 that vehicle 2is running in the forcible electric running mode in which the simulatedengine sound is inhibited. Such a record may constitute a circumstantialevidence if an accident will unfortunately occur due to an injuredperson unable to notice a silent approach of vehicle 2. Thus, as hasbeen previously mentioned, a driver who sets the forcible electricrunning mode becomes more careful in driving under such setting.

On the other hand, if pedestrian detection by motion sensor 64 isdetermined in step S84, or if an approach of vehicle 2 to a crosswalk isdetermined in step S86, or if the frequent repetitions of alternatingbrake 1 and accelerator operations are determined in step S88, the flowgoes to step S102 in every case. In step S102, engine sounds indicationprocess similar to step S60 in FIG. 3 is carried out. Further, in stepS104, engine sounds generation process similar to step S62 in FIG. 3 iscarried out. The flow then goes to step S98, in which it is directed torecord on EDR unit 68 the fact of generating the simulated engine soundsin those case.

Upon completion of the direction of EDR unit recording, the flow goes tostep S106 to check whether or not an operation to stop vehicle 2 is madeby brake 1. If such an operation is not detected in step S106, the flowgoes back to step S84 to repeat steps S84 to S106 unless the stopoperation is detected in step S106. On the other hand, the stopoperation is detected in step S106, the flow goes to the end to advanceto step S26 in FIG. 2.

According to the embodiment above, it should be noted that the detectionin one of steps S84 to S88 prevents the driver from optionallyinhibiting generation of the simulated engine sounds even by setting theforcible motor running mode to basically seek silent running. In otherwords, in such a case that the existence of a pedestrian in the vicinityof vehicle 2 or the approach of vehicle 2 to a crosswalk is detected,generation of the simulated engine sounds is superior to the silent runby electric motor 32 for the purpose of keep safety of pedestrians.Further, it should be also noted that the automatic change frominhibition to generation of the simulated engine sounds in response tothe detection in step S88 of the repeated alternation of operations ofbrake 1 and accelerator 3 is advantageous for pedestrians to easilynotice and get off vehicle 2 and also advantageous for vehicle 2 tosmoothly go ahead in a narrow street filled by pedestrians. The variousfeatures disclosed in the flow of FIG. 4 are not only applicable tohybrid vehicles, but also to electric vehicles having no gasolineengine.

FIG. 5 is a flowchart showing the detailed function of the simulatedengine sounds generation process in steps S18 and S22 in FIG. 2, stepS62 and step S104 in FIG. 4. If the flowchart starts, it is checked instep S112 whether or not the simulated engine sounds are generated. Ifnot, the flow goes to steps led by step S114 for newly startinggeneration of the simulated engine sounds. Firstly in step S114, theultrasonic sound for guide dog is inhibited. This is for such a casethat the flow of FIG. 5 results by way of step S74 in FIG. 3 or step S96in FIG. 4, through which the ultrasonic sound has started to begenerated. Of course, if ultrasonic is not generated, nothing functionsin step S114.

Next in step S116, the simulated engine sounds start to be generated insuch a manner that the volume of them softly increased from zero to thelevel of real engine sound. This is for copying the start of real enginesound not to astonish people in the vicinity of vehicle 2 with suddenand artificial emergence of the simulated engine sounds. The desirednatural rise of the simulated engine sounds is controlled by the volumechanging pattern data 50 of sound memory 46 in FIG. 1. Or,alternatively, the volume of the initial rise can be controller by amore simplified pattern. Step 118 follows the initial rise of thesimulated engine sounds controlled by step S116. On the other hand, ifit is determined in step S112 that the simulated engine sounds have beenalready generated, the flow directly goes to step S118.

In step S118, it checked whether or not any change in operation made. Ifany change is detected in step S118, the flow goes to step S120 to carryout the operation related volume or tone changing process, in whichengine sound data 48 is modified in volume or tone by referring to atable in sound memory 46 showing the relationship between the volumechanging pattern 50 and the related operation at operating portion 6,the flow then advancing to step S122. On the other hand, if no change isdetected in step S118, the flow directly goes to step S122.

In step S122, it is checked whether or not the environmental noisepicked up by outside microphone 44 is over a predetermined limit, whichis so determined that pedestrians in the vicinity of vehicle 2 hardlynotice the approach of vehicle 2 unless the volume is increased to alevel greater than that of real engine sound. If it is determined instep S122 that the environmental noise is less that the limit, the flowgoes to step S124 to check whether the weather is foul by means ofweather sensor 66 detecting rain drops or low barometric pressure inwhich high environmental noise by rain or wind is presumed. If a foulweather is not detected in step S124, the flow goes to step S126 tocheck whether or not an existence of a pedestrian putting up umbrellaexists in the vicinity of vehicle 2 by means of processing imagecaptured by camera unit 70. If no pedestrian with open umbrella isdetected in step S126, the flow goes to step S128.

In step S128, the date of clock 16 is utilized to check whether or notit is in late-night time zone. If it is in late-night, the flow goes tostep S130 to check whether or not the environmental noise picked up byoutside microphone 44 is under a predetermined limit, which is of a soquiet level that the real engine sounds is considered to be harmful. Ifnot, the flow goes to step S132. In this case, the simulated enginesounds of a standard volume which is comparable to that of the realgasoline engine will not harm the acoustic environment. Thus, it ischecked in step S132 whether or not the current simulated engine soundsis of the standard volume. If not, the flow goes to step S134 to softlyadjust the volume from the high or low volume to the standard volumeprior to going to step S136. On the other hand, if it is determined instep S132 that the current simulated engine sounds is of the standardvolume, the flow directly goes to step S136.

On the contrary, if it is determined in step S122 that the environmentalnoise is over the limit, the flow goes to step S140 to check whether ornot the current simulated engine sounds is of the high volume. If not,the flow goes to step S142 to softly increase the volume from thestandard or low volume to the high volume prior to going to step S136,the high volume being greater that that of the real gasoline enginesounds. On the other hand, if it is determined in step S140 that thecurrent simulated engine sounds is of the high volume, the flow directlygoes to step S136. Further, if the foul whether is detected in step S124or a pedestrian with open umbrella is detected in step S126, the flowgoes to step S140 to carry out the similar control to attain the highvolume.

On the other hand, if it is determined in step S130 that theenvironmental noise at late-night is under the limit, the flow goes tostep S144 to check whether or not the current simulated engine sounds isof the low volume. If not, the flow goes to step S146 to softly lowerthe volume from the standard or high volume to the low volume prior togoing to step S136, the low volume being less that that of the realgasoline engine sounds. On the other hand, if it is determined in stepS144 that the current simulated engine sounds is of the low volume, theflow directly goes to step S136. The limit for step S130 is higher thanthe limit for step S52 in FIG. 3. In other words, the simulated enginesounds are generated in permissibly low volume with environmental noiseunder the limit for step S130 in contrast to that the simulated enginesounds are not generated at all with environmental noise under the limitfor step S52. This means the limit for step S130 is of a level in whichsuch environmental noise exists as to drown out tire noise. Thus, thesimulated engine sounds in the lower volume is necessary under the limitfor step S130 for pedestrians to hear vehicle 2 approaching them.

In step S136, it is checked whether or not a predetermined operation isdone, such as one of an operation of select lever 7 for reverse travel,an operation of blinker lever 9 and an alternating operations of brake 1and accelerator 3. If one of such predetermined operations is detectedin step 136, the flow goes to step S138 for carrying out the volumemodification process, in which volume of the simulated engine sounds aremodified to copy the change in volume of the real gasoline enginepeculiar to the predetermined operation, the flow then going to the end.On the other hand, if none of the predetermined operations is detectedin step S136, the flow directly goes to the end. The detail of volumemodification process in step S138 is explained later. In FIG. 5, thevolume is changed among discrete three levels, such as low, standard andhigh volumes. Alternatively, however, the number of the levels may beincreased to achieve more sensitive control, or the volume may becontinuously changed.

FIG. 6 is a flowchart showing the detailed function of the volumemodification process in steps S138 in FIG. 5. If the flowchart starts,it is checked in step S152 whether or not an operation of select lever 7for reverse travel. If the reverse travel operation is detected in stepS152, the flow goes to step S154 to softly increase the volume of rearspeaker unit 58 relative to that of front speaker unit 56 to change thevolume balance between the two speakers. This is for effectivelynotifying pedestrians behind vehicle 2 of the rear travel thereof. Inthe case of the forward travel, on the contrary, the volume valance isso set that the volume of front speaker unit 56 is greater that thatrear speaker unit 58. In other words, the volume of rear speaker unit 58is lowered or muted in the case of the forward travel. The flow thengoes form step S154 to step S156. On the other hand, if the select leveroperation for reverse travel is not detected in step S152, the flowdirectly goes step S156.

In step S156, it is checked whether or not an operation of blinker lever9 for right turn. If such a right blinker operation is detected in stepS156, the flow goes to step S158 to softly increase the volume of rightspeaker unit 60 relative to that of left speaker unit 62 to change thevolume balance between the two speakers. This is for effectivelynotifying pedestrians on the right side of vehicle 2 of the right turnthereof. In the case of the straight travel, on the contrary, the volumevalance is so set that the volume of right speaker unit 60 is equal tothat that left speaker unit 62. Or alternatively, both the right speakerunit 60 and left speaker unit 62 are muted in the case of straighttravel. The flow then goes form step S158 to step S160. On the otherhand, if the blinker lever operation for right turn is not detected instep S156, the flow directly goes step S160.

In step S160, it is checked whether or not an operation of blinker lever9 for left turn. If such a left blinker operation is detected in stepS160, the flow goes to step S162 to softly increase the volume of leftspeaker unit 62 relative to that of right speaker unit 60 to change thevolume balance between the two speakers. Similarly to the case of rightturn, this is for effectively notifying pedestrians on the left side ofvehicle 2 of the left turn thereof, the flow then going to step S164. Onthe other hand, if the blinker lever operation for left turn is notdetected in step S160, the flow directly goes step S164. The functionsof changing the volume balance between speaker units carried out insteps S156 to S162 are useful not only for the purpose of right or leftturn, but also for the purpose of selectively notifying pedestrians onthe right-front or left-front of vehicle 2 of the approach thereof inthe case of the straight travel. In such a case, the balance change maybe caused by a special switch independent from blinker lever 9 for thepurpose of avoiding confusion.

In step S164, it is checked whether or not frequent repetitions ofalternating operations of brake 1 and accelerator 3 are made. The checkin step S164 is achieved by firstly detecting the successive operationsof brake 1 and accelerator 3 made within a short period and by secondlyconfirming that it is within a time frame from the last detectedoperation. In other words, if a time has past over the time frame withno further detection of the operation of brake 1 and accelerator 3, stepS164 determines that the brake/accelerator repeated alternation hasterminated. If it is determined in step S164 that frequent repetitionsof alternating operations of brake 1 and accelerator 3 are now beingmade, the flow goes to step S166 to check whether an operation ofaccelerator 3 is newly made within the time frame started from the lastdetection. If not, the flow goes to step S168 to check whether anoperation of brake 1 is newly made within the time frame started fromthe last detection. If not, the flow goes back to step S164 to checkagain whether or not the time frame has past. Thus, steps S164 to S168are repeated unless a new operation of brake 1 or accelerator 3 isdetected within the time frame for waiting for the new operation made.

If an operation of accelerator 3 is detected in step S166 or anoperation of brake 1 is detected in S168, the flow goes to step S170 inany of the case for making a one-shot peak of volume by softy increasingand then decreasing the volume once a detection of the operation ofbrake 1 or accelerator 3 Step S170 may be modified not to make aone-shot peak but to make a plurality of softly repeating peaks for onedetection of the operation of brake 1 or accelerator 3. The flow thengoes from step S170 to step S172. On the other hand, if no frequentrepetitions of alternating operations of brake 1 and accelerator 3 isdetected in step S164 at all or it is determined in step S164 that nonew operation is detected within the time frame from the last detection,the flow directly goes to step S172.

In step S172, it is checked whether or not the predetermined operationcausing the flow of FIG. 6 is ended. In other words, it is checked instep S172 whether or not the operation of select lever 7 for reversetravel or the operation of blinker lever 9 is ended. Further, it ischecked in step S172 whether or not the time frame is over with no newoperation detected since the last detection. If it is not detected instep S172 that the predetermined operation is ended in accordance withthe above manner, the flow goes back to step S152 to repeat steps S152to S172 unless the end of the predetermined operation is detected. Bymeans of the repetition, the volume of the simulated sounds change inaccordance with natural and soft wave pattern in response to frequentrepetitions between operations of brake 1 and accelerator 3. On theother hand, if it is detected in step S172 that the predeterminedoperation is ended, the flow goes to step S174 to softly reset enginevolume balance to the normal condition for straight forward travel, theflow then going to the end.

FIG. 7 is a flowchart showing the detailed function of the simulatedengine sounds indication process in steps S16 in FIG. 2, S60 in FIGS. 3and S102 in FIG. 4. If the flowchart starts, it is checked in step S182whether or not vehicle 2 is stopping. If vehicle 2 is stopping, the flowgoes to step 184 to direct select lever indicator 40 to blink. Selectlever indicator 40 is for indicating one of select lever positions, “P”,“R”, “N”, “D”, and “L”, on which the driver is assumed to have his orher eyes for starting to drive vehicle 2. By means of the blinking ofselect lever indicator 40, accordingly, the driver is naturally informedof the fact that the simulated engine sounds are generated outsidevehicle 2. The flow then goes from step S184 to step S186. On the otherhand, if it is determined in step S182 that vehicle 2 is not stopping,but running, the flow goes to step S185 to stop the rather bothersomeblink of select lever indicator 40, the flow then going to step S186.Step S185 is for functioning in the moment of starting vehicle 2 tocancel the blink once initiated in step S184 which functions only whenvehicle 2 is stopping. In other words, step S185 has no function if theflowchart of FIG. 7 is started during vehicle 2 has already beingrunning without blinking of select lever 40.

In step S186, it is directed to change the color for indication ofspeedometer 42, such as the color of indicating needle or indicatingdigit. For example, the color of speedometer indication is basicallychanged between gasoline engine running and electric motor running.Further, the color of speedometer indication upon electric motor runningwith the simulated engine sounds is set to the same color as that ofgasoline engine running. Thus, in the case of running with enginesounds, the color of speedometer indication is the same, such as inorange color, regardless of whether the sounds outside vehicle 2 arecaused by the real gasoline engine or by the simulated engines soundsgenerator. On the contrary, in the case of silent running without enginesounds, the color of speedometer indication is changed into a clearlydifferent one, such as green color. In the case of the above example, itis directed in step S186 to change the color for indication ofspeedometer 42 from green to orange.

In step S190 it is checked whether or not motion sensor 64 detects anypedestrian. If any pedestrian is detected, the flow goes to step S192 todirect speedometer indication to blink. In the case that a pedestrianexists in the vicinity of vehicle 2, it is important for both the driverand the pedestrian to communicate with each other by means of wellsharing the fact that the simulated engine sounds are generated outsidevehicle 2. The blink of speedometer indication is an effective help forthe driver to become aware of the simulated engine sounds generation foravoiding such an inconsistency that the driver gets a false idea of nogeneration of the simulated engine sounds though the pedestrian actuallyhears the simulated engine sounds. The flow then goes from step S192 tostep S194. On the other hand, if no pedestrian is detected in step S190,the flow directly goes to step S194.

In step S194 it is checked whether or not vehicle 2 is on a narrow road.If not, the flow goes to step S196 to check whether or not vehicle 2 isrunning on a road without sidewalk. If not, the flow further goes tostep S198 to check whether or not vehicle 2 is approaching a crosswalk.If the approach to a crosswalk is detected in step S198, the flow goesto step S200, in which it is generally directed to change a partialcolor of the indication of the detected special area on map 22controlled by vehicle navigation system 20, the flow then going to stepS202. In the case of the detection in step S198, the change in color iscaused at crosswalk area on map 22. Similarly, if it is determined instep S194 that vehicle 2 is on a narrow road, or it is determined instep S196 that vehicle 2 is running on a road without sidewalk, the flowgoes to step S200 to direct the change in color of indication for thedetected corresponding area on map 22. Thus, if the generation ofsimulated engine sounds is caused by a run in a special area, theindication of the generation of simulated engine sounds is made on map22 controlled by vehicle navigation system 20. On the other hand, if noapproach to a crosswalk is detected in step S198, which means that a runin a special area is not detected in any of steps S198 to S198, the flowgoes t step S202 with no indication for the generation of the simulatedengine sounds caused.

In step S202, it is checked whether or not an operation of select lever7 for reverse travel. If not, the flow goes to step S204 to checkwhether or not an operation of blinker lever 9. If not, the flow furthergoes to step S206 to check whether or not frequent repetitions ofalternating operations of brake 1 and accelerator 3 are made. If thefrequent repetitions of alternating operations are detected, the flowgoes to step S208, in which it is generally directed to change color ofrelating operating portion indication, the flow then going to step S210.In the case of the detection in step S206, the change in color is causedwith respect to indication of brake 1. Similarly, if the operation ofselect lever 7 for reverse travel is detected in step S202, or anoperation of blinker lever 9 is detected in step S204, the flow goes tostep S208 to direct the change in color of indication for the detectedcorresponding operation. In other words, the color of indicating selectlever position, “R” is changed in the former case, while the color ofblinker indication is changed in the later case. Thus, if the generationof simulated engine sounds is caused in relation with an operation ofvehicle 2, the indication of the generation of simulated engine soundsis made at the indicating portion originally prepared for indicating therelated operation. On the other hand, if no frequent repetition ofalternating operations of brake 1 and accelerator 3 is detected in stepS206, which means that no related operation is detected in any of stepsS202 to S206, the flow goes t step S210 with no indication for thegeneration of the simulated engine sounds caused.

In step S210, it is directed to prepare for a direction to reset theindication to a normal condition with no simulated engine soundsgenerated, the flow then going to the end. Step S210 is necessary forresetting the indication to the normal condition in response to thedirection to be made in step S30 in FIG. 2, or step S70 in FIG. 3, orstep S92 in FIG. 4. Namely, various indication changes caused o informthe driver of the generation of the simulated engine sounds are eachcancelled to return to the normal indicating condition in synchronismwith the termination of the simulated engine sounds in response to oneof the above mentioned directions.

The above mentioned various features according to this invention are notonly applicable to the disclosed embodiment, but to any other embodimentwhich seeks warm and safe coexistence of both vehicles and pedestriansin various situations with the advantage of hybrid vehicles or electricvehicles capable of silent run maintained as much as possible.

What is claimed is:
 1. A vehicle capable of low noise runs comprising:an electric motor for driving the vehicle; a sound generator arranged togenerate simulated engine sounds outside the vehicle for pedestrians tohear the vehicle; a decider arranged to decide whether or not to havethe sound generator generate the simulated engine sounds; and acontroller arranged to change the level of the simulated engine soundsin accordance with a predetermined manner.
 2. The vehicle according toclaim 1, wherein the controller is arranged to smoothly increase thelevel of the simulated engine sounds when the decider decides to havethe sound generator start generating the simulated engine sounds.
 3. Thevehicle according to claim 1, wherein the decider is arranged to havethe sound generator generate the simulated engine sounds in response toa detection of a pedestrian in the vicinity of the vehicle.
 4. Thevehicle according to claim 1, wherein the decider is arranged to havethe sound generator generate the simulated engine sounds in response toa detection that the vehicle is close to a crosswalk.
 5. The vehicleaccording to claim 1, wherein the decider is arranged to have the soundgenerator generate the simulated engine sounds in response to adetection that the vehicle is on narrow road.
 6. The vehicle accordingto claim 1, wherein the decider is arranged to have the sound generatorgenerate the simulated engine sounds in response to a detection that thevehicle is on a road with no sidewalk.
 7. The vehicle according to claim1 further comprising a vehicle navigation system unit, wherein thedecider is arranged to make the decision in response to the vehiclenavigation system unit.
 8. The vehicle according to claim 1 furthercomprising an electronic toll system unit, wherein the decider isarranged to make the decision in response to the electronic toll systemunit.
 9. The vehicle according to claim 1 further comprising a cameraunit, wherein the decider is arranged to make the decision in responseto the camera unit.
 10. The vehicle according to claim 1 furthercomprising an event data recorder unit arranged to record the decisionby the decider.
 11. The vehicle according to claim 10 further comprisinga manually setting unit, wherein the decider is arranged to make thedecision in response to the manually setting unit.
 12. The vehicleaccording to claim 1 further comprising a manually setting unit, whereinthe decider is arranged to normally make the decision in response to themanually setting unit and to have the sound generator generate thesimulated engine sounds under a predetermined condition regardless ofthe manually setting unit.
 13. The vehicle according to claim 1, whereinthe controller is arranged to make a peak of the level of the simulatedengine sounds by softly increasing and then decreasing the simulatedengine sounds.
 14. The vehicle according to claim 13 further comprisingan operating portion for operation of one of a brake and an accelerator,wherein the controller in arranged to make the peak in response to theoperation at the operating portion.
 15. The vehicle according to claim 1further comprising a gasoline engine for driving the vehicle, whereinthe controller is arranged to set the level of the simulated enginesounds to one of a level greater than the real gasoline engine sounds, alevel substantially equal to the real gasoline engine sounds and a levelless than the real gasoline engine sounds.
 16. The vehicle according toclaim 1, further comprising an operating portion for operation of thevehicle, wherein the sound generator includes a plurality of generatingportions, and wherein the controller is further arranged to change thebalance among the level of the simulated engine sounds from theplurality of generating portions in response to the operation at theoperating portion.
 17. The vehicle according to claim 1, furthercomprising a visual indicator arranged to inform the driver inside thevehicle of the decision by the decider.
 18. A vehicle capable of lownoise runs comprising: an electric motor for driving the vehicle; asound generator arranged to generate simulated engine sounds outside thevehicle for pedestrians to hear the vehicle including a plurality ofgenerating portions; an operating portion for operation of the vehicle;and a controller arranged to change the balance among the levels of thesimulated engine sounds from the plurality of generating portions inresponse to the operation at the operating portion.
 19. The vehicleaccording to claim 18, wherein the controller is arranged to change oneof the balances of the simulated engine sounds between the front and therear of the vehicle and between the right and the left of the vehicle.20. A vehicle capable of low noise runs comprising: an electric motorfor driving the vehicle; a sound generator arranged to generatesimulated engine sounds outside the vehicle for pedestrians to hear thevehicle; a decider arranged to decide whether or not to have the soundgenerator generate the simulated engine sounds; and a visual indicatorarranged to inform the driver inside the vehicle of the decision by thedecider.